The present invention relates to a urea tank for a transport vehicle, a unit comprising a diesel tank and said urea tank, a transport vehicle comprising said unit, in addition to a mechanism for the simultaneous diesel and urea delivery, for the two aforementioned tanks.
The invention relates more specifically to transport vehicles having a diesel engine, which therefore use diesel as fuel. By way of a non-limitative example, such vehicles could be buses, coaches or even lorry-type vehicles.
Generally, this type of transport vehicle comprises a body mounted on wheels. It is also equipped with a diesel tank, allowing fuel to be supplied to the engine of said vehicle.
For ecological purposes, particularly in light of the EURO 4 regulation, it is now common to mix, among other things, urea with the aforesaid diesel fuel. Thus, said urea, which is stored in a separate tank, is sprayed directly into the exhaust gases of the diesel engine, causing the breakdown of certain noxious pollutants.
An example of a fuel tank integrated with a module containing a fine reduction fluid (urea) is described in the utility patent
This having been specified, this invention aims to improve the prior art solutions by associating two tanks of urea and diesel respectively, specifically in terms of maintenance and ease of use.
For this purpose, the object of the invention is a unit comprising a diesel tank and an urea tank for a transport vehicle, specifically a bus or coach, comprising:
According to further characteristics:
A further object of this invention is a unit comprising a diesel tank and a urea tank as described above, the hole of the diesel tank and the hole of the urea tank being placed side by side.
According to further characteristics:
A further object of this invention is a transport vehicle, specifically a bus or coach, comprising a body, a diesel engine, as well as a unit comprising a diesel tank and a urea tank as described above.
According to further characteristics:
Lastly, a further object of this invention is a device for the simultaneous diesel and urea delivery for a unit comprising a diesel tank and a urea tank, as described above, having a body, two distribution nozzles joined to said body, as well as two conduits suitable to connect each nozzle with a respective source of diesel or urea.
A particular object of the present invention is a unit comprising a diesel tank and an urea tank, a transport vehicle comprising said unit, in addition to a mechanism for the simultaneous diesel and urea delivery, as described in the attached claims, which are considered an integral part of the present description.
The invention will be described below, with reference to the attached drawings, given purely by way of non-limiting example, in which:
Typically, the engine 2 and the diesel tank 10 are joined by two ducts 21 and 22 for the supply and return of the diesel. Moreover, the urea tank is joined, also in a known manner, to a pump 22. For this purpose, two respective supply and return lines 241 and 242 connect said tank to said pump. The latter is connected, by means of a conduit 26, to a metering valve 28, which itself is connected to an atomiser which is not illustrated, to allow the urea to be sprayed into the exhaust gases.
For this purpose, the exhaust pipe is numbered 3, while the spraying operation is indicated schematically by the arrows f. Thus, following this operation, which is of a known type, exhaust gases with a reduced pollutant content are discharged into the atmosphere in the direction of arrow F.
Furthermore, the engine 2 and the urea tank 20 are joined by two ducts 301 and 302, ensuring the circulation of the hot water from the engine. Said hot water is suitable to circulate in a coil (not illustrated), equipping the urea tank 20.
Also included is a solenoid valve 32 on the duct 301, ensuring the arrival of hot water from the engine in the tank direction. As will be seen in more detail below, said solenoid valve is adapted to stop the inflow of said hot water when the temperature thereof reaches a preset value.
Said tank 20 comprises a main body 34, arranged in a lower area, from which two upper compartments 36 and 38 extend, one next to the other. Said two compartments 36 and 38 are separated, at their lower end, by a partition 40. In other words, the opposite surfaces 361 et 381 of said two compartments define an interstitial volume V, the height H of which is much greater than its width l.
Compartment 36, which is to be filled with urea, is equipped with an upper hole 362, joined to a cap 363, in a known manner. There is also a valve 364 which has the function of ensuring that the tank is neither pressurized nor depressurized.
The second compartment 38, used for air entrapment as shall be seen below, is equipped with a valve 382, which is for example like those marketed by the company DELTA COMPONENT. Said valve is such that it will not let air escape outside of the tank when there is a sharp rise in pressure inside the tank, arising particularly upon filling with urea. On the other hand, when the pressure is gradually increased or decreased inside said tank, said valve is suitable to allow air to escape outside the tank.
Lastly, compartment 38 is equipped with a level gauge 383, of a known type. The function of said gauge is to provide an indication of the level of urea inside the tank, through the level indicator on the instrument panel, as well as ensuring heating through the coil.
The urea tank 20 embodiment, as described above, shall now be explained in more detail.
Let us firstly recall that urea has a freezing point of around -11°C, so that it has an inherent risk of freezing in use. During refilling, the corresponding nozzle is placed into the hole 362, provided in the upper section of the compartment 36, so that the urea flows into the main body 34 of the tank 20. Due to the presence of the partition 40, urea does not rise up significantly into the second compartment 38.
In these conditions, as illustrated in
In extremely cold weather, leading to the partial freezing at least of the urea stored in the tank 20, urea solidifies and its volume 44' increases gradually, resulting in a slow rise in pressure inside the tank. As a result of this, as mentioned above, the valve 382 allows air to escape, outside the tank, following arrow f1 in
In these conditions, urea is free to occupy at least part of the second compartment 38, without causing deformation or even explosion of the tank 20. Note that the compartment 38 is of an adequate size to ensure the entrapment of an air volume of around 15% of the total volume of the tank 20, in the case of fully liquid urea.
If we suppose that the urea in tank 20 has frozen at least partially, it is possible to heat up urea by means of the engine. Thus, with reference to
This then allows the vehicle to be started up, along with the depollution of its exhaust gases. Also note that the presence of the solenoid valve 32 is advantageous. Indeed, it is adapted to stop the flow of hot water in the direction of the tank, if the water temperature is for example above 65°C, preventing urea from degrading, specifically into ammonia.
The diesel tank 10 rests on a cradle 18 (
Moreover, the urea tank 20 is equipped with its own fastening legs 29, allowing it to be joined to the cradle 18 of the diesel tank 10. Therefore, the urea tank 20 is mounted in a detachable manner onto the cradle 18, which itself allows the diesel tank 10 to be fastened in a detachable manner onto the vehicle chassis.
In these conditions, it is possible to easily detach the urea tank 20 from the diesel tank 10, without however disassembling the latter from the vehicle chassis. This detachment is illustrated in
An operator is thus able to separately manipulate the urea tank 20, which is practical in terms of its reduced volume and weight. Lastly, said operator replaces the urea tank 20 into the recess 14, so that the unit 4 formed by the two tanks 10 and 20 once again forms a solid block, as shown in
In the lower part of the housing 50, the latter is indented with a recession 54, which is joined to a pipe 56 extending along the wall 52, inside the latter. Therefore, said pipe 56 is not significantly visible on the outside.
When the tanks 10 and 20 are filled, diesel and/or urea is likely to spill outside the inner volume of the tank. This residual volume of fuel is then channelled by gravity towards the recession 54, and then runs into the pipe 56. In these conditions, this residual fuel does not flow noticeably onto the visible part of the body, which is advantageous in aesthetic terms.
Furthermore, there are two tubes 661 and 662, each of which runs between a fuel source, of diesel or urea respectively, as well as a corresponding nozzle 641 or 642. It will also be noted that the distance separating these two nozzles 641 and 642 is the same distance as that between the two holes 162 and 362.
Therefore, thanks to the use of this delivery device 60, the two tanks can be filled by means of a single filling operation. This allows considerable time savings, which is advantageous particularly with a view to automating this stage of refuelling.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.